Leveling device for cable-tool drills



June 15, 1948. H. w. THORNBURG 3,209

LEVELING DEVICE FOR CABLE-TOOL DRILLS Filed Sept. 9, 1944 2 Sheets-Sheet 1 INVENTOR. 17 f ATTORNEYS Patented June 15, 1948 LEVELING DEVICE FOR CABLE-TOOL DRILLS Herbert w. Thornburg, South Milwaukee, wn,

assignor to Bucyrus Erie Company, South Milwaukee, Wia, a corporation of Delaware Application September 9, 1944, Serial No. 553,437

3 Claims.

to new and useful imdevices for cable-tool My invention relates provements in levelin drills.

The cable-tool drill is a highly specialized, but well-known, form of drill for drilling vertical holes in earth or rock. The drilling tool is successively hoisted by a rope and then dropped against the bottom of the hole which is being drilled,

In the past it has been customary to block up the main frame of the machine with timbers before starting drilling. Mechanical jacks have sometimes been used, in place of such cribbing.

The objects of such jacking or cribbing have been: (1) to level the machine preliminary to drilling, this being'especially necessary in view of the vertical nature of the drilling operation; (2) to broaden the support base beyond the limits of the traction mechanism, as otherwise the lifting and dropping of the drilling tools at a point beyond the traction base would introduce great instability; (3) to relevel during drilling; and (4) to protect the traction mechanism, and the connections between it and the main frame, from jarring strains.

The substitution of hydraulic jacks for mechanical jacks, would serve to speed-up the levcling operation, but would introduce no further advantages along the above lines; in fact, would introduce some further complications, as will be mentioned in a moment.

Neither cribbing nor jacks (not even hydraulic jacks) were adapted to releveling plus centering. and furthermore provided no lateral stability. Lateral stability is essential, to keep the line which suspends the drilling tools centered over the hole.

Also, when first I contemplated using hydraulic jacks, I found that the control-valves could not stand the strains imposed on the system by the drilling operation, and that any attempt at introducing lateral stability imposed undue bending strains on the jacks themselves. Furthermore I found it necessary to protect my jacks from external damage.

Accordingly the principal objects of my invention are: (1) to provide an hydraulic leveling system; (2 to provide a leveling system which will aiford lateral stability; (3) to prevent the lateral stabilizing means from imposing bending strains on my hydraulic apparatus; (4) to protect my hydraulic apparatus from external damage; and (5) to protect my control valves from drilling shocks.

I attained these advantages by employing, in-

stead of hydraulic jacks, telescoping spuds, rigidly attached to the main frame of my drill, and operated by hydraulic mechanism; by locating these hydraulic mechanisms inside the spuds, which latter are wholly enclosed so as to protect these mechanisms; by so connecting these operating mechanisms to the spuds, that the spuds take all the bending strains, and the mechanisms are under merely pure compression; and finally by adding means to close the pressure conduit between each spud and its control-valve, during drilling. v

In addition tomy principal objects, above stated, I have worked out a number of hovel and useful details, which will be readily evident as the description progresses.

My invention consists in the novel parts and in the combination and arrangement thereof, which are defined in the appended claims, and of which one embodiment is exemplified in the accompany- ;ing drawings, which are hereinafter particularly described and explained.

Throughout the description the same reference number is applied to the same member or to similar members.

Figure 1 is a side elevation of a cable-tool drill containing my invention.

Figure 2 is a more detailed showing of my hydraulic system, omitting most of the drilling machine, except the directly supporting structural portions thereof.

Figure 3 is a vertical section of one of my spuds, contracted.

Figure 4 is a corresponding vertical section of the same spud expanded.

Referring now to Figure l, we see that i I is the main frame of my drilling machine, I2 is a casing, inserted in the upper end of the hole being drilled. I3 is any convenient form of ground support for my drill, preferably but not necessarily of the endless .tread variety.

A drilling-tool I4 is suspended in the hole by a rope 15, which passes over a crown-sheave (not shown) at the top of mast l6, thence around spudding-sheave H, on spudding-beam l8, thence around heel-sheave ill at the rear pivot of beam 18, and thence around heel-sheave ill at the rear pivot of beam l8, and thence to a winch drum 20. The beam is is reciprocated by motor 23, acting through intermediate unnumbered gearing and crank 22 and pitman 2|. Various methods, wellknown in the art, can be used to pay-out and take-in rope l5.

Tool 14 may be steadied by toolguide 24'.

The description thus far is conventional and,

as. to its details, constitutes no part oi my invention. I 1 v I have added 'theretoiront spud 25 and two rear spuds 20, togive a three-point support to the machine during'drilling; and to attain the objects recited earlier herein.

Turning-now to Figure 2, we see .tha-til is a pump, operatedby motor 28, and drawing oil from a sump 28 through pipe 30, and forcing the oil through pipe v3| to triple valve 32; This valve canbe 01 any conventional sort, provided each pumped oil back to the sump through'pipe 33.

The details of this valve do not constitute any part of my invention.

The valve 82 is controlled by three valve-handies 34. h v

From valve 32 to the top of each cylinder runs a pipe 35, and to the bottom of each cylinder a pipe 38. In each pipe 3.5 there is a simple sto valve 31. Y i Let us now turn to Figures 3 and 4, and consider the details of each spud and its associated hydraulic operating mechanism.

First there is the telescoping spud, consisting of an outer casing 38, built rigid with some por- .tionof the frame II, and an inner casing 39.

The outer casing 38 has a cap 40, secured'thereto in any convenient manner, as by boltsdi. The

The rigid attachment of the upper portion of the spud to the main frame of the machine enables the spud to hold the machine against lating stresses, and places .the cylinderepiston aseral movement.

inside the spud, causes the spud to take all bendsembly under pure compression whenever the spud is under load. Also this construction protects the cylinder-piston assembly from dirt and other damage.

When the spuds have been adjusted by use of valve 32, the closing of valves 31 takes all shock strains off of valve 32.

Having now described and illustrated one form of my invention, I wish it to be understood that my invention is not to be limited to the specific form or arrangement of parts herein described and shown.

1. In a iluid-pressureleveling system for a cable-tool drill, the combination of a plurality of ground-engaging spuds; a source of fluid; a pump to force the fluidselectiveiy to each spud, through a conduit, to forcibly expand the spud; anda control valve, to selectively control the expaninner casing slides on guide-rings 42, secured to the outer casing in any convenient manner. The details of the mounting of these 'rings are the invention of another, although the idea of having such rings is mine.

Pivoted to the cap '40, as at -48, is a cylinder- 64, containing a piston 45, and piston rod 68. The piston rod is pivotally attached to the inner spud casing 39, as at 41.

The bottom end of the inner spud casing is universally attached to a ground-engaging shoe 48, as at 49. This point is loose, so that in fact the bottom end of the inner spud casing rests quasi-universally in the cavity in the shoe. The combined effect of the above-mentioned pivotal attachment of the piston rod to the inner spud casing, and the just-mentioned pivotal attachment of the inner spud casing to the-shoe, is a universal gimbal connection between piston rod and shoe.

Although preferable, it is not essential that the cylinder-piston assembly be oriented with the cylinder up and the piston-rod down. Accordingly, whenever I refer to a pipe as running to the "top of the cylinder,-I mean to that part of the cylinder away from the piston rod.

sion, contraction, and holding of the spuds; ,each spud and associated mechanism consisting of an upper casing rigidly securedto the frame ofthe drill, a lower casing telescoping with theupper casing and having a ground-engaging shoe, guide means between the-two casings to take all bending stresses, and a cylinder-piston assembly within the casing, the cylinder being pivoted to one casing and the piston-rod to .the other, so that the assembly takes pure compression only.

2. A leveling system according to claim 1, char.- acterlzed by having in each conduit single means between the valve and the cylinder-piston as sembly, to closethe conduit, thereby locking its I HERBERT w. THORNBURG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,538,167 Chappell et al May 19, 1925 2,247,141 Twyman June 24. 1941 2,252,741 Thornburg Aug. 19, 1941 2,268,017 Busick, Jr., et a1. Dec. 30, 1941 2,365,169 Billings Dec. 19, 1944 

